Job prospects...

I take psychology as a subject at school and I think I want to take it as a major at university, but I'm not sure what kind of jobs this degree will get me later on. Would it be better if I studied this with another subject as well?

Hi Ben,
To answer your question - it depends on what career path you want to take. If you want to practice psychology, majoring in the subject is your best bet. However, be prepared that you will have to undertake postgraduate study if you want to become a clinical psychologist.
If you are interested in a career outside of the mental health field, it will probably be beneficial to study another subject as well (whether as a minor, double major, or a conjoint degree). Psychology complements a lot of other subjects such as Law, Management, Marketing and Education.
Cheers,
Amy